Download archlinux.iso https://www.archlinux.org/download/
Create an Arch Linux installer USB drive https://wiki.archlinux.org/index.php/USB_flash_installation_media#Using_dd
Insert USB, reboot, press F-10, choose to boot from USB
Connect to wifi
ip link set wlp1s0 up
wpa_supplicant -B -i wlp1s0 -c <(wpa_passphrase <SSID> "<passphrase>")
dhcpcd wlp1s0
Download and run Arch Linux Fast Installer
wget archfi.sf.net/archfi
sh archfi
Follow installation guide https://wiki.archlinux.org/index.php/Installation_guide
The pacstrap step doesn't include
wpa_supplicant
. Use this version of archfi instead of the original version if you need wireless after the installation.